1. Field of the Invention
The present invention relates to a negative photo-resist composition which is a pattern-forming material in the production of a semiconductor. More particularly, the present invention relates to a negative photoresist composition which has high sensitivity, high resolution and high resistance to dry etching and is suitable for far ultra-violet or excimer laser lithography.
2. Description of the Related Art
Recently, integrated circuits have been highly miniatuarized; but with the increase of a degree of integration it has become required to form a submicron order pattern. In particular, excimer laser lithography makes it possible to produce next-generation 64 MDRAM and 256 MDRAM. With the change of a light source, a resist should have heat resistance, a good film thickness retention and a profile and also the following properties:
a) Having a high sensitivity to the above light source, and
b) Having a high resolution.
Japanese Patent Kokai Publication No. 293339/1989 discloses a composition containing a polymer which comprises hydroxystyrene, a cross linking agent and a photo-acid generator such as p-toluene sulfonates. However, this composition has unsatisfactory sensitivity and resolution, and does not satisfy the above requirements.